This competitive renewal application seeks continued support for a four-year study originally funded by the National Cancer Institute (1R01 CA82822). Funding for the original project began on 9/1/99 and will end on 6/30/03. A one year no-cost extension will expire on 6/30/04. The specific aims of the original study were to: 1) determine the severity and course of fatigue associated with treatment for early stage breast cancer; 2) characterize the cognitive, affective, and behavioral manifestations of fatigue associated with treatment for early stage breast cancer; and 3) test the utility of a cognitive-behavioral model designed to explain individual differences in fatigue among women receiving treatment for early stage breast cancer. Our work under the original proposal has yielded new insights into the severity, course, predictors, and correlates of fatigue during the active treatment period and during the first six months following completion of active treatment in women who received either chemotherapy followed radiotherapy or radiotherapy only. We believe that, by continuing to follow these two treated groups of patients as more time elapses following treatment completion, we have an opportunity to add significantly to knowledge about the nature of fatigue and its manifestations during an extended period of breast cancer survivorship. We note, however, the absence in our original design of comparison groups that would allow for determination of the extent to which the fatigue and related cognitive, behavioral, and affective problems exhibited by patients following completion of active treatment differ from "normal." In consideration of these issues, the specific aims of this competing continuation application are to: 1) determine the severity, course, and predictors of fatigue in the two treated groups over the first 3.5 years following completion of active treatment; 2) identify cognitive, behavioral, and affective problems associated with fatigue in the two treated groups over the fast 3.5 years following completion of active treatment; and 3) determine whether women who have completed active treatment for breast cancer experience greater fatigue and more related affective, cognitive and behavioral problems than women with no history of cancer matched for age, education, and geographic residence. To accomplish these aims we propose to: assess the two treated groups of patients again 3 years after completion of the final 6-month follow-up assessment currently being conducted; and recruit samples of women without cancer matched for age, education, and geographic residence with patients in each treated group and assess them on two occasions three years apart in order to generate comparison data. Provision of five years of continued funding will allow for uninterrupted follow-up of patients currently on study, the opportunity to collect complete 6-month and 3.5-year follow-up data on the two treated groups currently being followed, and the opportunity to collect complete initial and 3- year follow-up data matched comparison groups of women with no history of cancer.